But loss of subsidies could cost about 60,000 people in Mississippi, which has the highest percentage nationwide, 94 percent, of ACA enrollees who receive federal subsidies, according to a study by Avalere Health, a national consulting firm.

Mississippi also still has one of the highest rates of uninsured people, at nearly 22 percent according to another recent study.

Two federal court of appeals issued conflicting rulings on Tuesday. One, from a three-judge panel in the District of Columbia, ruled that Obamacare law restricts subsidies to state-run health care exchanges and they should not be allowed in federally run exchanges. But another ruling, from the Fourth Circuit Court of Appeals upheld the subsidies.

Mississippi is one of 36 states that refused to create a state-run health care exchange to provide insurance under Obamacare, which Bryant, Reeves and most other state Republican leaders oppose.

In statements on Tuesday both Bryant and Reeves expressed hope the D.C. ruling will hamstring the ACA.

Bryant said: "As I have long said, I believe the IRS violated the law when it authorized massive taxpayer funded subsidies in the 36 states that declined to establish Obamacare exchanges, thereby triggering unwarranted taxes and mandates on both individuals and employers. Today's ruling is another step in dismantling Obamacare and returning the control of individual health care to the people."

Reeves said: "Once again, the work of Obama, Pelosi and Reid is struck down in court. Time and again, the courts continue to find the flaws and disregard for the Constitution in Obamacare."

The Mississippi House Democratic Caucus on Tuesday criticized Bryant and other Republican leaders for their opposition in 2013 to a state-run health care exchange.

"As a result, if this case stands it will cost Mississippi families thousands of dollars per year thanks to our Republican leadership in Jackson," the statement said. "... Mississippi's Republican leadership is against a state run insurance exchange no matter what it costs families. Couple their extremism in opposition to a state run exchange with Governor Bryant's refusal to accept federal funds to save Mississippi hospitals, and this Republican regime is well on the way to dismantling community healthcare as we know it."